Conveyor belt support

ABSTRACT

The present invention relates to extensible endless conveyor belt support structures and systems. A support structure has vertical support members (8) connected by V-shaped arrangements of pivotally connected (17, 19) link members (7, 9). By mounting at least the upper belt run rollers (4) on the vertical supports (8) the load can be more effectively supported whilst providing a relatively high ratio of extended to contracted length. By using telescopically extendable (14, 15) vertical supports (8), any increase in overall height of the support structure upon contraction thereof is minimized or avoided. By also having detachable lower belt run rollers (23) the support structure can be inserted into an endless conveyor belt installation without dismantling or even stopping running thereof. The invention also provides systems including setting devices for holding the support structures in their contracted form and deploying and collecting them into and from their extended conditions. Preferably the setting device includes a retractor means for drawing in the support structure during collection thereof.

The present invention relates to supports for endlessconveyor belts, andmore particularly to a longitudinally extendable and retractable endlessconveyor belt support structure and a setting device suitable for use inconjunction with a remotely sited belt storage device.

In many endless conveyor belt applications the belt loading pointadjacent to the return end of the conveyor advances and retreats more orless frequently thereby requiring that the conveyor length should beextended or retracted. Erection and dismantling of a conventionalconveyor belt support structure can be very time-consuming andlabour-intensive resulting in significant down-time of the conveyor andhence loss of production.

Recently there has been proposed in WO90/08717 and U.S. Pat. No.4,860,878 a telescopically extendable support structure made up ofinterlinked A-frames which close up and open out in generallyconcertina-like manner. The upper and lower belt run support rollers aremounted generally centrally of the limbs of the A-frames so that thestructure has a relatively large overall height even in its deployedcondition and the height is substantially further increased in thecontracted condition of the support structure when the support structureis being moved into place or positioned awaiting deployment. This isparticularly undesirable in the case of underground mining andtunnelling applications where overhead clearance and effective widthsare often very restricted. In addition, whilst these systems may permita degree of longitudinal extension or contraction of the supportstructure, a degree of assembly is generally necessary for insertioninto an existing endless conveyor belt. Alternatively the endless beltitself may require dismantling should a transporting device be deployedloaded with fully assembled belt supports for insertion therein. Acorresponding degree of dismantling is necessary when removing thecontracted support structure from the conveying system, thereby stillrequiring a significant amount of labour as well as interruptingoperation of the conveyor belt especially where dismantling thereof isrequired.

A further significant disadvantage of the use of an A-frame structure isthat the weight of the belt and material being carried thereon iscarried on inclined support members which results in bending stressesbeing applied to them and the need for suitably strong chains or othersecondary links for preventing splaying out of the inclined supports.This also results in longitudinal extension of the support structurebeing substantially restricted in order to contain such problems.

It is an object of the present invention to avoid or minimize one ormore of the abovementioned disadvantages.

The present invention provides an endless conveyor belt supportstructure which is longitudinally extendable between an extendedcondition for supporting the endless conveyor belt, and a contractedcondition, which support structure comprises a plurality of pivotallyinterconnected support members at opposite sides of the supportstructure, at least some of said support members being substantiallyrigidly interconnected by crossmembers to corresponding support membersat the opposite side of the support structure, at least some of saidsupport members mounting upper belt run support roller means at an upperedge portion of the support structure and at least some of said supportmembers mounting lower belt run support roller means, said supportmembers being interconnected so as provide for longitudinal extensionand contraction of said sides of the support structure in generallyconcertina-like manner, characterised in that said support structurecomprises a plurality of generally vertically extending support membersinterconnected by generally V-shape arrangements of pivotally connectedpairs of linked support members in which the V-shape opens out or closesup for extension or contraction of the support structure.

Preferably the generally vertically extending support members aretelescopically extensible from a contracted form in the longitudinallycontracted condition of the structure to an extended form in thelongitudinally extended condition of the structure.

The present invention also provides an endless conveyor belt supportstructure which is longitudinally extendable between an extendedcondition for supporting the endless conveyor belt, and a contractedcondition for insertion into and removal from an endless conveyor beltinstallation, which support structure comprises a plurality of pivotallyinterconnected support members at opposite sides of the supportstructure, at least some of said support members being substantiallyrigidly interconnected by crossmembers to corresponding support membersat the opposite side of the support structure at an upper edge portionof the support structure, at least some of said support members mountingupper belt run support roller means at an upper edge portion of thesupport structure and at least some of said support members detachablymounting lower belt run support roller means, (preferably detachably)said support members being interconnected so as provide for longitudinalextension and contraction of said sides of the support structure ingenerally concertina-like manner, at least some of said support membersbeing longitudinally extendable between a contracted form in thelongitudinally contracted condition of the support structure, and anextended form in the longitudinally extended condition, so that theoverall height of the support structure can be reduced in itslongitudinally contracted form, whereby insertion and removal of thesupport structure may be effected substantially without dismantling ofthe conveyor belt or the support structure apart from detaching andreplacement of said lower belt run support roller when detachable lowerbelt run support rollers are used.

It will be appreciated that various forms of support in this form ofsupport structure of the present invention. In one preferred form thereis provided a plurality of generally vertically extending supportmembers interconnected by generally V-shaped arrangement of pivotallyconnected pairs of link support members in which the V-shape opens outor closes up for extension or contraction of the support structure, thevertically extending support members being longitudinally extensiblee.g. telescopically extensible. In the fully extended form of thesupport structure the V-shape can be opened out into a substantiallystraight form though preferably the included angle at the apex islimited to slightly less than 180°, preferably an angle of from 140° to179°, most preferably from 150° to 178°, e.g. 176°, in order tofacilitate collapsing of the V-shape during retraction. In contrastA-frame type structures such as those used in U.S. Pat. No. 4,860,878and WO 90/08717 have substantially restricted opening angles in order tobe able to support the weight of the loaded conveyor belt and carry itat a suitable height above the ground.

Conveniently upper edge portions of substantially all the verticallyextending support members are interconnected by the cross-members.Advantageously the cross-members are used to support belt support rollermeans.

The present invention also provides an endless conveyor belt supportstructure which is longitudinally extendable between an extendedcondition for supporting the endless conveyor belt, and a contractedcondition for insertion into and removal from an endless conveyor beltinstallation, which support structure comprises a plurality of pivotallyinterconnected support members at opposite sides of the supportstructure, at least some of said support members being substantiallyrigidly interconnected by crossmembers to corresponding support membersat the opposite side of the support structure, at least some of saidsupport members mounting upper belt run support roller means at an upperedge portion of the support structure and at least some of said supportmembers detachably mounting lower belt run support roller means, saidsupport members being interconnected so as provide for longitudinalextension and contraction of said sides of the support structure ingenerally concertina-like manner, and comprising a plurality ofgenerally vertically extending support members interconnected bygenerally (preferably inverted) V-shape arrangements of pivotallyconnected pairs of link support members in which the V-shape opens outor closes up for extension or contraction of the support structure.

With the cross-members mounted at the upper edge portion of the supportstructure and the lower belt run roller means detachable, the supportstructure can be inserted and removed to and from a laterally adjacentposition between upper and lower belt run portions. Conveniently thecross-members are used as part of the mounting means for upper belt runsupport rollers, especially where these are of the so-called "transom"type. It is nevertheless also possible to use separate mounting meanswith, for example, the support belt run support rollers suspended fromsupport members at opposite sides of the support structure. The upperand/or lower belt run portions can, if necessary be displaced verticallyto facilitate insertion and removal of the support structure. It ishowever a particular advantage of the present invention that insertionand removal can be effected without the need for actually dismantlingthe belt, and in a particularly preferred aspect, without even having tointerrupt operation of the belt conveyor.

In a further respect the present invention provides a setting devicesuitable for use in insertion and/or removal of a conveyor belt supportcassette comprising a length of a support structure of the inventionin/from an endless conveyor belt system, said setting device comprisingan elongate platform means having:

a cassette receiving and/or ejecting section; and a cassetteinstallation and/or recovery section, said platform means being formedand arranged for supporting, in use, a said cassette between the upperand lower belt runs, said receiving and/or ejecting section havinglaterally displacable cassette transfer means formed and arranged fortransferring a cassette in a longitudinally contracted form between asetting device loading/unloading position adjacent one side of thesetting device, and a position between the upper and lower belt runs,and bringing the cassette to/from a position for displacement to/fromthe installation/recovery section, said platform means being formed andarranged for supporting thereon the cross-members of the supportstructure of the invention, as successive segments of the cassette areextended/contracted during advance/retreat of the cassette along theinstallation/recovery section.

In yet another aspect the present invention provides an endless conveyorbelt support system comprising a support structure of the invention anda setting device suitable for use in holding said support structure inits longitudinally contracted form and longitudinal extension andcontraction of said support structure, said setting device comprising acarriage means formed and arrange for carrying said support structure inits longitudinally contracted condition, and progressively deploying andextending said support structure behind the carriage means as saidcarriage means is advanced, said carriage means being provided with aretractor means formed and arranged for engagement with successiveportions of the support structure and drawing them onto said carriagemeans for longitudinal contraction of said support structure.

In a still further aspect the present invention provides an endlessconveyor belt support system comprising a support structure of theinvention and a setting device suitable for use in insertion and/orremoval of a conveyor belt support cassette comprising a length of saidsupport structure in/from an endless conveyor belt system, said settingdevice comprising a carriage means having:

a cassette receiving and/or ejecting section; and a cassetteinstallation and/or recovery section, said carriage means being formedand arranged for supporting, in use, a said cassette substantiallybetween the upper and lower belt runs, said receiving and/or ejectingsection having laterally displacable cassette transfer means formed andarranged for transferring a cassette in a longitudinally contracted formbetween a setting device loading/unloading position adjacent one side ofthe setting device, and a position between the upper and lower beltruns, and bringing the cassette to/from a position for displacementto/from the installation/recovery section, said carriage means beingformed and arranged for supporting thereon the support structure, assuccessive segments of the cassette are extended/contracted duringadvance/retreat of the cassette along the installation/recovery section.

Preferably the carriage means is provided with a retractor means formedand arranged for engagement with successive portions of the supportstructure and drawing them onto said carriage means for longitudinalcontraction of said support structure.

Further preferred features and advantages of the invention will appearfrom the following detailed description given by way of example of somepreferred embodiments illustrated with reference to the accompanyingdrawings in which:

FIG. 1 is a side elevation of part of an endless conveyor belt systemwith a partly extended support structure of the invention within asetting device therefor;

FIG. 2 is a plan view of the support structure of FIG. 1;

FIG. 3 is a detail perspective part view of the support structure ofFIG. 1 in its deployed form;

FIG. 4 is a partial perspective view of the setting device of FIG. 1;

FIG. 5 is a detail view corresponding to that of FIG. 3 of a modifiedsupport structure embodiment;

FIG. 6 is a detail perspective view of another support structure similarto that of FIG. 3 but with a modified roller mounting disposition;

FIG. 7 is a side elevation generally corresponding to that of FIG. 1 ofanother embodiment of the invention suitable for cyclic operation;

FIG. 8 is a detail view of the embodiment of FIG. 7 showing part of theretractor means thereof; and

FIGS. 9 and 10 are transverse sectional elevations of an embodimentsimilar to that of FIG. 1.

FIG. 1 shows part of an endless conveyor belt system C in which upper(carrying) 1 and lower (returns), 2 runs of an endless conveyor belt 3are supported on respective rollers 4, 5. A discrete belt supportstructure in the form of a longitudinally extendable "cassette" 6comprises a plurality of pivotally interconnected support members 7, 8at each side 9 and 10 of the conveyor belt 3, rigidly connected to eachother by cross-members 11.

In more detail (see also FIG. 3) the support members include uprightmembers 12 forming the opposite sides of generally H-shaped supports 13,whose cross-pieces are constituted by the cross-members 11. The lower,ground engaging, portions 14 of the uprights 12 are telescopicallyretractable into the upper portions 15 thereof. In the region of theirjunction 16 with the cross-members 11, the upright members 12 arepivotally connected 17 to the outer ends of generally (inverted)V-shaped arrangements of pairs of link support members 18 pivotallyinterconnected 19 via a depending roller support member 20 or a smallconnecting piece 30 each provided with respective abutment portions 20a,30a, for limiting opening out of the link support members 18 at the apex21 of the V-shape to a shallow V-shape as generally indicated in thedrawings. The roller support member 20 is generally hook-shaped at itsbase 22 for detachably receiving and supporting thereon a lower returnbelt run support roller means in the form of a suspended idler rollerset 23.

The H-shaped supports 13 mount upper carrying belt run support rollermeans in the form of transom type idler roller sets 24 formed andarranged for supporting the upper conveying run 1 of the belt 3 in atroughed configuration for helping to contain material 25 being carriedon the belt 3.

As shown in FIG. 2 the cassette 6 is initially stored in alongitudinally contracted form on a setting device 26 which is used tolocate the cassette 6 in the conveyor belt installation and then insertit thereinto and remove it therefrom. In the contracted form of thecassette 6, the lower portions 14 of the upright support members 12 areretracted into the upper portions 15 and the connecting V-shaped linkmember arrangements 7 closed-up together in generally concertina-likemanner, so that the cassette 6 has a restricted length and heightwhereby insertion thereof between the upper and lower runs 1, 2 of thebelt 3 from a position 34 or 35 (FIG. 2) alongside the belt 3 isfacilitated. Once the cassette 6, still supported by the setting device26, has been inserted between the upper and lower runs 1, 2 of the belt3, which may be temporarily diverted away from each other to increasethe separation therebetween, the cassette 6 may begin to be extended.Initially a first upright support member at one end of the cassette 6,is pulled out within the setting device 26 allowing the lower portion 14automatically to drop down from the upper portion 15 to bring theupright 12 into its fully extended condition. Locking pins 27,preferably automatically engagable, are provided to retain the lowerportion 14 fully extended. At the same time the V-shaped support memberarrangement 18,20/30 connected thereto begins to open out lowering thehook-shaped idler roller support 20 which then automatically collects areturn belt run support roller 23 from a roller store 28. When thissupport member segment 18, 20/30 of the cassette 6 is fully opened outthe next upright 12 is pulled out within the setting device 26 andextended and the process repeated until the whole cassette (and anysubsequent cassettes required to suit the desired conveyor lengthrequirement has been fully deployed along the floor the feet 29 of theextended upright support members 12 resting on said floor 36. Removal ofa cassette in a retreat mining system is generally a reversal of theabovedescribed process with the added feature that within the V shapedsupport member arrangement 18, 20/30 is a latch device 33 whichautomatically locks the unfolded V shaped support member arrangement inits deployed open position requires to be unlatched either manually orby interengaging cam means or the like.

In the retreating or retracting mode, vertical 31 and horizontal 32steering jacks (see FIG. 2) are provided to ensure correct positioningof the setting device 26 adjacent one end of the deployed beltsupporting structure prior for collection and refolding thereof backinto its concertina-like form 6.

To assist the satisfactory operation of the conveyor belt 3 adjustmentmechanisms 36, 37 are provided on the upper and lower belt supportingroller assemblies 4, 5 respectively for the control and alignment of theconveyor belt 1, 2 by a single operator stationed at one side of theconveyor C which is normally the travelling or access side.

In more detail the adjustment mechanism 36 provided on the upper beltsupporting roller assembly 4 is in the form of a single slot means 38extending generally parallel to the conveying direction, through whichis received a securing bolt 39 or the like in generally known manner.The slot means 38 is provided on a bracket means 40 on the upper end 41of the vertical support member 12 so that adjustment of the outer end 42of the proximal one 43 only of the three rollers 42, 43, 44 extendingacross the width of the upper belt-run 3 to support it, forwards orbackwards, can be made thereby varying the angle of inclination of theproximal roller 43 relative to the belt and to the other two rollers 42,44. Surprisingly it has been found that this adjustment alone issufficient to correct any mis-alignment of the belt without at the sametime subjecting the belt to any significant additional stress. Anexample such an adjustment is shown in FIG. 2 at 43'. Conveniently theadjustment mechanism 36 is provided at both sides of the supportstructure to allow use thereof at whichever side happens to beaccessible in any given situation.

The setting device 26 will now be described in more detail withreference to FIG. 4 in conjunction with FIGS. 1 and 2. In general thesetting device 26 comprises a large sled structure 45 with a connectingsection CS used to coupled the setting device 26 to a return end stationor other apparatus at the advancing and/or retreating end of theconveyor C (not shown); a handling section HS where contracted cassettes6 are inserted into or removed from the conveyor system C; a storagesection SS for holding one or more contracted cassettes 6; and aninstallation and/or recovery section IRS.

In more detail the sled structure comprises parallel spaced apartelongate members 46 forming a platform 47 on which the cross-members 11of the `H`-shaped supports 13 rest, the elongate members 46 beingsupported by legs 48 on base runners 49 provided with self-cleaningsurfaces 50 inclined for shedding any material falling thereonto. Thehandling section HS is provided with a tray 51 slidable laterallyoutwardly of the setting device 26 to a ground level loading/unloadingposition alongside the latter as shown in FIG. 2 at 52, 53 and inchain-line in FIG. 4. The tray 51 includes handling section portions 46aof the platform members 46 so that when the tray 51 is lowered to groundlevel and slid outwardly to its loading/unloading position shown indashed outline, a cassette 6 is loaded onto these platform memberportions 46a which join up to the rest of the platform members when thetray is drawn back into the setting device 26 and raised (see below). Inuse a cassette 6 is brought up to the tray 51 in its loading/unloadingposition and placed thereon. The tray 51 is then pulled back into thesetting device 26 by a tray deployment piston-cylinder means 54 and nextraised up to the level of the platform 46 by tray elevatingpiston-cylinder means 55. As shown in FIG. 1 the coupling section CS ofthe setting device is provided with a pair of upper belt run supportrollers 56 which may be driven upwards by support roller elevatingpiston-cylinder means 57 to raise temporarily the upper belt run to anelevated position 3' where it passes over the handling section HS inorder to facilitate the lateral movement of the cassette into and out ofthe setting device 26 within the handling section HS.

Once the cassette 6 has been raised up on the tray 51 it is advancedalong the platform 47 into the storage section SS to be coupled to apreviously loaded cassette 6 by making pivotal connections 17 betweenlink support members 18 at the trailing end 58 of the previously loadedcassette 6 and upright support members 12 at the leading end 59 of thenewly loaded cassette 6, using a cassette shifting piston-cylinder means60 provided with a reversible cassette engagement head 61. As shown inFIGS. 1 and 4 the lower belt run 2 is diverted downwardly close alongthe ground beneath the tray 51 and cassette handling piston-cylindermeans etc. by means of guide rollers 62.

As shown in FIG. 4, the setting device 26 also includes at each side anelongate support track 63 immediately outwardly of the platform members46, for engaging the feet 29 of the upright support members 12. In thehandling and storage sections HS, SS the tracks 63 are slightly belowthe upper surfaces 64 of the platform members 46 so that the insideedges 65 of the feet 29 run alongside the outer edges 66 of the platformmembers 46. In the installation and recovery section IRS, the tracks 63are inclined downwardly 67 to distal end sections 68 which extendalongside the runners 49. Thus when an upright support 12 of a cassette6 passes along the installation and recovery section IRS as the settingdevice 26 advances along the ground underneath (see FIG. 1), the lowerportions 14 of the upright supports 12 are progressively lowered as theytraverse the sloping portions 67 of the tracks 63, whilst thecross-members 11 supported by the platform members 46 are maintained ata constant height. This has the further advantage of avoiding he needfor bodily lifting the belt and any material on it during contraction ofthe support structure. When the feet 29 reach the distal end sections 68the lower portions 14 are fully extended and the catches 27 provided onthe upper portions 15 engage to secure the lower portions 14 in theirextended positions. The feet 29 then traverse the horizontal distal endsections 68 of the tracks 63 for a short distance to ensure that thelink-support members 18 in a given portion of the cassette are fullyopened out and "locked" into their open configurations ensuringstability of the roller support structure (e.g. against leaning over ofthe upright supports 12 etc.) before the given portion of the cassetteis expelled onto the ground. (The link and upright supports 18, 12 areconveniently stabilised relative to each other by the provision ofmutually engaging abutment surfaces 69 and retractable wedges 70).

The distal end portions 71 of the platform members 46 are alsodownwardly inclined to lower the now fully extended `H`-shaped supports13 onto the ground when they are expelled from the setting device 26.The tips 72 of these end portions 71 may be levelled out 73 for thispurpose, but normally would be fully inclined for cassette collection(as used for example in retreat mining applications).

Towards an outer end 74 the installation and recovery section IRS isprovided with a return belt run support roller store 28 into whichreturn belt support rollers 5 are manually inserted for automaticpick-up by the hook shaped base 22 of roller support members 20 (seeFIG. 3).

The setting device 26 may of course include various conventional devicessuch as a return belt plough 75 for cleaning the lower belt run 2.

It will be appreciated that various modification may be made to theabove described embodiment without departing from the scope of thepresent invention. Thus for example where the conveyor belt supportstructure does not require to support the conveyor belt off the ground,this being achieved by some other means such as wall mounted brackets 80as shown in FIG. 5 or roof slinging (not shown), the upright supports 81may be considerably shorter in the extended position of the cassette andthus do not necessarily need to be telescopically extendable. Also thenovel type of tracking adjustment used on the upper belt run rollermeans 4 could be replaced by any other suitable adjustment means, suchas, for example, the type used on the lower belt run roller means.

Yet another variation is shown in FIG. 6 wherein the upper belt runroller means 4 is mounted at an upper portion 82 of the lower beltroller support 20 connected to the V-shaped arrangements of like supportmember pairs 18 at the apex 21 thereof. Although this has thedisadvantage of raising the height of upper belt run when the supportstructure is contracted this may be acceptable where headroom is notrestricted. With this type of arrangement the extra loading on the linksupport members from both conveying and return belt runs will usuallymean that it is not necessary to provide a latching/locking or wedgingmechanism (70).

FIG. 7 shows another simplified embodiment suitable for use in a cyclicmode and like parts corresponding to those in the previous embodimentsare indicated by like reference numbers. In this case the setting device83 simply has an installation and recovery section IRS generally similarto that in FIG. 1 with a single length of support structure 84 securedthereto 84a. The setting device is however provided with a retractormeans 85 in the form of a hydraulically operated piston and cylinder 85awith a deflectable hook means 86 at the free end 87 of the piston rod 88(see also FIG. 8). The hook means 86 is arranged so that it is depressedby a cross-member 11 of the support structure when one piston rod isextended and then springs back up on the far side 89 of the cross-member11 so that upon retraction of piston rod 88 the support structure isdrawn onto the setting device 83. By repeating this process andreciprocating the piston and cylinder 85 substantially the whole of thesupport structure can be progressively drawn onto the setting device 83and into the installation/recovery section IRS thereof.

The piston and cylinder 85 has a stroke generally equal to or slightlylarger than the spacing between successive cross-members. In a typicalarrangement with cross-members 11 between the vertical support members13 (only) and the support structure having a repeating unit pitch of1.39 m there is used a stroke of 1.40 m.

Such a retractor means is particular suitable for use in a cyclic modeof operation where the setting device is progressively advanced awayfrom an existing conventional fixed or permanent support structure 96until the support structure 84 has been fully extended. The supportstructure is then drawn back onto the setting device 83 until it isfully contracted, the permanent conveyor belt support structure 96 thenbeing extended in conventional manner to catch up with the anchorportion 93 of the extensible support structure 84. The process can thenbe repeated with the setting device being progressively advanced againuntil the extensible support structure has been fully extended. Thusunlike in the first embodiment the setting device only moves forward andthe use of the retractor means avoids the possibility of prematurelongitudinal collapse of the extended support structure remote from thesetting device during retreat of the setting device as used in theprevious embodiments for achieving contraction of the extensible supportstructure. Thus the need for any latching or locking means on the hingedsupport links may be avoided thereby allowing use of a substantiallysimpler form of pivotal hingeing interconnection 90 between the inclinedsupport members 7, 9. Such a system can typically extend up to 25 m froma contracted length of 5.6 m.

In order to prevent the hook 86 of the retractor means 84 interferingwith deployment of extensible support structure the setting device isprovided with a deflector plate 91 at the extreme end of the pistonrod's travel so that the hook 86 is deflected into a non-engagingposition.

The distal end 92 of the extensible support structure is provided withan anchor portion 93 in the form of a more or less heavy sled body withground engaging runners 94 which resist displacement of the anchorportion 93 as the setting device 83 progressively advances deploying theextensible structure behind it. If desired the anchor portion 93 mayalso be secured to the free end 95 of the permanent or fixedconventional support structure 96 but this is not essential.

The anchor portion 93 is also provided with an overbridge 97 to providesafe access to the far side of the conveyor system though it will beappreciated that one advantage of preferred forms of the invention isthe substantially minimized access required to the far side.

As discussed hereinbefore the use of a retractor means allows asignificantly simpler form of hinge construction 90 between the two"inclined" link members 7,9 without any special latching or lockingmeans for securing them in their fully "opened-out" disposition and withonly a single pivot instead of two as before which gives increasedstability during extension and contraction.

Although as noted hereinbelow the use of detachable bottom rollersreduces the weight carried by the platform support members 46 it will beapprecited that it is not essential for the bottom rollers to bedetachable especially where external platform support members are usedfor engaging outwardly projecting lugs on the support members of thesupport structure.

FIG. 9 is a cross-section through the handling section HS of a systemsimilar to that of FIG. 1. In this case a two-section folding track 99is hingedly mounted 100 at the side 101 of the handling section HS forsupporting the movable tray 51 which is used to carry a cassette 6between an outboard loading/unloading position 34 (see FIG. 2) to theside of the setting device and an inboard insertion position. As shownin FIG. 9 once the cassette 6 has been brought inboard of the settingdevice it is raised on the tray 51 to the level of the storage sectionSS as shown in dashed outline.

FIG. 10 is a cross section through the installation and recovery sectionIRS and shows the cross-members 11 of the support structure beingsupported on the cantilevered forward ends 46b of the platform supportmembers 46 (see also FIG. 4) as well as an overbridge 97 similar to thatin FIG. 7. By using detachable bottom rollers the weight of thecontracted support structure on the cantilevered forward ends 46b of theplatform support members is reduced. Nevertheless it will be appreciatedthat the bottom rollers could also be more permanently secured.

Further advantages of the invention that may be mentioned are theopportunity for improved safety as a result of the reduced requirementfor manual erection and dismantling of conveyor belt support structure,and increased speed for extension and contraction of endless conveyorbelt systems leading to reduced, and in some cases substantiallyeliminated, down-time.

I claim:
 1. An endless conveyor belt support structure which islongitudinally extendable between an extended condition for supportingthe endless conveyor belt, and a contracted condition, which supportstructure comprises a plurality of pivotally interconnected supportmembers at opposite sides of the support structure, at least some ofsaid support members being substantially rigidly interconnected bycrossmembers to corresponding support members at the opposite side ofthe support structure, at least some of said support members mountingupper belt run support roller means at an upper edge portion of thesupport structure and at least some of said support members mountinglower belt run support roller means, said support members beinginterconnected so as provide for longitudinal extension and contractionof said sides of the support structure in generally concertina-likemanner, characterised in that said support structure comprises aplurality of generally vertically extending support membersinterconnected by generally V-shape arrangements of pivotally connectedpairs of link support members in which the V-shape opens out or closesup for extension or contraction of the support structure.
 2. A structureaccording to claim 1 wherein said generally vertically extending supportmembers are telescopically extensible from a contracted form in thelongitudinally contracted condition of the structure to an extended formin the longitudinally extended condition of the structure.
 3. An endlessconveyor belt support structure which is longitudinally extendablebetween an extended condition for supporting the endless conveyor belt,and a contracted condition for insertion into and removal from anendless conveyor belt installation, which support structure comprises aplurality of pivotally interconnected support members at opposite sidesof the support structure, at least some of said support members beingsubstantially rigidly interconnected by crossmembers to correspondingsupport members at the opposite side of the support structure at anupper edge portion of the support structure, at least some of saidsupport members mounting upper belt run support roller means at an upperedge portion of the support structure and at least some of said supportmembers mounting lower belt run support roller means, said supportmembers being interconnected so as provide for longitudinal extensionand contraction of said sides of the support structure in generallyconcertina-like manner, at least some of said support members beinglongitudinally extendable between a contracted form in thelongitudinally contracted condition of the support structure, and anextended form in the longitudinally extended condition, so that theoverall height of the support structure can be reduced in itslongitudinally contracted form.
 4. A structure according to claim 1wherein at least said upper belt run support roller means are mounted onsaid generally vertically extending support members.
 5. A structureaccording to claim 1 wherein said lower belt run support rollers meansare detachably mounted on the support members whereby insertion andremoval of the support structure into and from a conveyor beltinstallation may be effected substantially without dismantling of theconveyor belt or the support structure apart from detaching andreplacement of said lower belt run support roller means.
 6. A structureaccording to claim 1 wherein is used an inverted V-shaped arrangement oflink support members.
 7. A structure according to claim 1 wherein saidlink support members are provided with stop means formed and arrangedfor restricting maximum opening of the V-shape to an angle of from 140°to 179°.
 8. A structure according to claim 7 wherein said opening isrestricted to an angle of from 150° to 178°.
 9. A structure according toclaim 1 wherein said support members are provided with latch meansformed and arranged for releasably securing said link support members inan opened out arrangement in the longitudinally extended condition ofthe support structure for preventing closing up of said link membersduring longitudinal contraction of the support structure, until saidlatch means have been unlatched.
 10. An endless conveyor belt supportsystem comprising a support structure according to claim 1 and a settingdevice suitable for use in holding said support structure in itslongitudinally contracted form and longitudinal extension andcontraction of said support structure, said setting device comprising acarriage means formed and arrange for carrying said support structure inits longitudinally contracted condition, and progressively deploying andextending said support structure behind the carriage means as saidcarriage means is advanced, said carriage means being provided with aretractor means formed and arranged for engagement with successiveportions of the support structure and drawing them onto said carriagemeans for longitudinal contraction of said support structure.
 11. Anendless conveyor belt support system comprising a support structureaccording to claim 1 and a setting device suitable for use in insertionand/or removal of a conveyor belt support cassette comprising a lengthof said support structure in/from an endless conveyor belt system, saidsetting device comprising a carriage means having:a cassette receivingand/or ejecting section; and a cassette installation and/or recoverysection, said carriage means being formed and arranged for supporting,in use, a said cassette substantially between the upper and lower beltruns, said receiving and/or ejecting section having laterallydisplacable cassette transfer means formed and arranged for transferringa cassette in a longitudinally contracted form between a setting deviceloading/unloading position adjacent one side of the setting device, anda position between the upper and lower belt runs, and bringing thecassette to/from a position for displacement to/from theinstallation/recovery section, said carriage means being formed andarranged for supporting thereon the support structure, as successivesegments of the cassette are extended/contracted during advance/retreatof the cassette along the installation/recovery section.
 12. A systemaccording to claim 11 wherein said carriage means is provided with aretractor means formed and arranged for engagement with successiveportions of the support structure and drawing them onto said carriagemeans for longitudinal contraction of said support structure.
 13. Asystem according to claim 10 wherein said retractor means is ofreciprocating action type.
 14. A system according to claim 10 whereinsaid carriage means is provided with a bottom roller collection stationand said support structure is provided with bottom roller mounting meansformed and arranged for engaging and picking up bottom rollers as saidsupport structure is deployed from the advancing carriage means.
 15. Asystem according to claim 10 wherein said bottom roller collectionstation is formed and arranged for engaging and dismounting of saidbottom rollers from said bottom roller mounting means as said supportstructure is longitudinally contracted onto said carriage means.
 16. Asystem according to claim 10 wherein said carriage means is formed andarranged for supporting thereon the cross-members of the supportstructure.
 17. A system according to claim 10, wherein a distal end ofsaid support structure is provided with an anchor portion including aheavy body with ground engaging means formed and arranged for resistingdisplacement of aid anchor portion longitudinally of the supportstructure.